600 Million Tonnes of Water Ice Found on the Moon

The latest announcement from NASA is that it's mini-SAR instrument aboard the Chandrayaan-1 lunar mission has revealed bulk water ice trapped in shadowed crater areas in the amount of 600 million metric tonnes:

What are the implications for further lunar exploration? What is the best way to investigatively follow up on this finding?

In light of this discovery, is it possible that liquid water may exist deep in the lunar underground, perhaps as aquifers trapped inside of impermeable rock layers? How far down would a lunar permafrost be expected to go?